During part load and hot day operations, gas and steam turbine rear stages may operate under severe off-design conditions due to reduced flow and pressure ratios. The conditions may result in efficiency losses. A contributing factor to this inefficiency is due to reduced enthalpy drop, which leads to inefficient operation of the turbine and/or the diffuser downstream thereof. One of the methods to increase the enthalpy drop during part load or hot day operations is via altering the last stage rotor blade (bucket). It would be desirable to modulate the throat area to stabilize the radial profile and other air flow properties in the turbine rear stages to increase efficiency during part load operation.